Tissue Plasminogen Activator and Plasminogen Activator Inhibitor-1 Gene Expression in Muscle after Maximal Acute Aerobic Exercise.

Carpenter RL, Lemmer JT, Francis RM, Knous JL, Sarzynski MA, Womack CJ. Tissue Plasminogen Activator And Plasminogen Activator Inhibitor-1 Gene Expression in Muscle After Maximal Acute Aerobic Exercise. JEPonline 2010;13(6):35-44. Animal studies suggest plasminogen activation in skeletal muscle is necessary for muscle repair. However, plasminogen activators have been studied little in humans. Therefore, the purposes of this study were to: 1) assess changes in skeletal muscle gene expression of fibrinolytic and coagulation factors 2) assess plasma activity of tPA and PAI-1 in response to an acute bout of maximal aerobic exercise, 3) determine if there is any relationship between muscle gene expression of tPA and PAI-1 with plasma activity levels. Six healthy, college-aged males volunteered blood and muscle samples prior to and immediately following a maximal treadmill exercise test. Muscle tissue was homogenized and purified RNA underwent RT- PCR using gene-specific primers for tPA and PAI-1 as well as biotynylation for microarray. Blood was analyzed via biofunctional immunosorbent assays for tPA and PAI-1 activity. A significant increase in tPA mRNA was seen with exercise (p=0.038) while PAI-1 mRNA showed no changes with the exercise. Muscle tPA activity showed no changes with the exercise bout. Plasma tPA showed a significant increase in activity (p<0.0001) while plasma PAI-1 activity had no change with the exercise bout. In conclusion, tPA synthesis increases in muscle following acute, high-intensity exercise and muscle production does not significantly contribute to plasma tPA increases seen with acute, high-intensity exercise. [ABSTRACT FROM AUTHOR]